This invention relates to a disk player system incorporating a disk sucking device which causes an information record medium in the form of a disk such as a phonograph record disk and a video disk (hereinafter referred to as "disk") to be sucked to the upper surface of a turntable of the player system by producing a state of a reduced pressure below an atmospheric pressure (hereinafter sometimes referred to as "vacuum") and utilizing this state of the reduced pressure for the sucking of the disk.
Disk sucking devices utilizing vacuum for sucking a disk to a turntable have been proposed for realizing reproduction of the disk in a desirable state in which warping of the disk is corrected by keeping the disk sucked to the turntable. FIG. 1(a) shows one of such prior art devices disclosed in the specification of U.S. Pat. No. 4,065,135. In this prior art device, a channel communicating a suction space a with a suction pump b (indicated by arrows) is provided. This channel is formed partly through a rotatable member d along an axis of rotation L of the rotatable member d and partly through a stationary member e fixed to a chassis of the player. A switching valve V is provided on the channel. When a disk f is to be reproduced, the suction space a is caused to communicate with the suction pump b by changing over of the valve V and the suction pump b is actuated to produce vacuum in the suction space a and thereby to suck the disk f to a turntable c. When the disk f is to be removed from the disk, the suction space a is caused to communicate with the atmosphere by changing over the valve V so that air is let in the suction space a. In FIG. 1, reference characters g and h designate packings, i a center spindle and M a driving motor.
The prior art disk sucking device in which the suction channel is provided in the turntable c is disadvantageous in that the device requires a complicated manufacturing process resulting in a high cost and that the device is not applicable to a turntable of an ordinary type of record reproduction system. Further, since the suction channel of this prior art device is formed through members which rotate relative to each other, sealing means must be provided between these relatively rotating members and this causes wow-flutter and adversely affects signal-to-noise ratio of reproduced signals. Furthermore, the suction channel in the prior art device is so long that sucking efficiency is rather low.
A major problem in such disk sucking divice is that air leakage makes it difficult to maintain a state in which a disk is sucked to a turntable for a long period of time. For compensating for such air leakage, the above described prior art disk sucking device employs a method according to which the suction pump b is driven each time the vacuum in the suction space a decreases beyond a predetermined degree. This method, however, requires a control system for detecting the degree of vacuum in the suction space a and driving the suction pump b in response to a detected signal. Besides, driving of the suction pump b during reproduction of the disk causes vibration which deteriorates the signal-to-noise ratio.
Another problem in such disk sucking device is to maintain an optimum degree of vacuum in the suction space. If the vacuum is too high, the disk sucked to the turntable will be injured whereas if the vacuum is too low, the disk will be disengaged from the turntable.
There has also been proposed a disk sucking device as shown in FIG. 1(b). In this device, annular lip-like seal members j and k made of rubber are provided on a turntable c in such positions as will support a disk f in portions immediately inside of a groove guard fa and immediately outside of a label fb of the disk f. By evacuating air from a space a defined by these annular seal members j and k and the disk f, the disk f is sucked toward the turntable c with the seal members j and k serving as sort of suckers and warping of the disk f thereby is corrected.
In this device, however, the periphery of the seal member j by which the disk f is sucked is liable to be bent downward to come apart from the disk f as shown in FIG. 1(c) so that the seal member j is in close contact with the disk f only in the limited portion indicated by reference character h and hence a seal thus provided is not entirely free from the air leakage. In order to enhance the sealing ability of the seal j, it could be made thinner but this would only result in a wavelike deformation of its periphery as shown in FIG. 1(d) thereby expediting the air leakage instead of reducing it. Same condition is also noted as to the seal member k.
Further, the above described prior art devices have a relatively small area for supporting the disk and this is disadvantageous in that it allows warping of the disk due to the sucking force.